Integrated Absorption-Compression Refrigeration for Waste Heat Use
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Solution Overview
Problem
Conventional HVAC&R systems face inefficiencies due to reliance on mechanical compression, high costs from electricity or shaft power, and low collection efficiency in solar thermal absorption chillers, particularly in applications where thermal energy is wasted or renewable energy sources are unstable.
Innovation Solution
An integrated refrigeration system combining vapor compression and absorption refrigeration cycles, where the absorption refrigeration cycle is fluidly coupled with the vapor compression cycle, utilizing a refrigerant and absorption solution to optimize pressure and temperature changes, and leveraging external heat sources like solar power or waste heat for efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If mechanical vapor compression is used, then refrigeration effect is achieved, but high operating costs and energy consumption occur
Solution Approach 1:
The patent combines mechanical vapor compression and absorption refrigeration cycles into a single integrated system. The compression chamber serves dual purposes: compressing refrigerant vapor while simultaneously absorbing heat to drive the absorption cycle. This merging allows the system to utilize waste heat from compression for refrigeration, reducing overall energy consumption while maintaining reliable cooling performance.
Solution Approach 2:
The patent replaces part of the mechanical compression function with an absorption mechanism. Instead of relying solely on mechanical work to compress and cool refrigerant, the system uses absorption of refrigerant vapor by an absorbent material, which is then driven by thermal energy from compression heat or external sources. This substitution reduces mechanical energy requirements and operating costs.
2Adaptability or versatility
If absorption refrigeration is used with solar thermal collectors, then renewable energy utilization is improved, but collection efficiency decreases due to high temperature lift requirements
Solution Approach 1:
The patent changes the operating parameters of the absorption cycle to match the output characteristics of flat plate solar collectors. By adjusting the absorbent-refrigerant pair and operating temperatures, the system operates efficiently at lower temperature lifts (30-50°C) that match solar collector output, thereby improving energy collection efficiency while maintaining renewable energy utilization.
Solution Approach 2:
The patent replaces high-temperature thermal systems with a low-temperature absorption system that can directly utilize solar thermal energy from flat plate collectors. This substitution enables effective use of renewable solar energy without the efficiency losses associated with high temperature lift requirements.
3Loss of energy
If thermal energy from engine exhaust and coolant is used, then waste heat recovery is improved, but system complexity increases
Solution Approach 1:
The patent designs the absorption chamber and heat exchange components to serve multiple functions: cooling the refrigerant, condensing vapor, and utilizing waste heat from engine exhaust or coolant. This multi-functionality allows waste heat recovery without proportionally increasing system complexity, as existing engine thermal management components are integrated into the refrigeration cycle.
Solution Approach 2:
The patent merges the waste heat recovery system with the refrigeration cycle by integrating the absorption chamber with the engine coolant or exhaust heat source. This combination allows simultaneous waste heat utilization and refrigeration operation without requiring separate, complex heat recovery equipment.
4Adaptability or versatility
If photo voltaic systems are used to power refrigeration, then renewable energy use is improved, but system cost increases due to additional components
Solution Approach 1:
The patent replaces electrical drive systems with thermal-driven absorption mechanisms. Instead of using photovoltaic panels to generate electricity for compressors, the system uses solar thermal energy to drive the absorption cycle directly. This substitution eliminates the need for power electronics, batteries, and complex electrical control systems, thereby reducing overall system cost while maintaining renewable energy utilization.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This integrated system enhances fuel efficiency, reduces component size, and lowers operating costs by utilizing thermal energy and renewable sources, achieving improved overall efficiency in HVAC&R applications.
Implementation Method 1
The absorber is fluidly coupled to the compressor and is configured to generate a mixture of refrigerant and absorption solution
Implementation Method 2
The desorber is fluidly coupled to the condenser and is configured to separate the refrigerant from the mixture as a vapor and increase the pressure of the refrigerant vapor
Implementation Method 3
when this refrigerant evaporates or boils, it takes some heat away with it, providing a cooling effect
Implementation Method 4
when this refrigerant evaporates or boils, it takes some heat away with it, providing a cooling effect
Implementation Method 5
condenses the hot, high pressure gas back to a liquid by heat exchange with a cool fluid, such as air or water
Data Source
AI summary
A refrigeration system is provided including a vapor compression cycle (20) having a condenser (22), and expansion valve (24), and evaporator (26) and a compressor (28). A refrigerant is configured to circulate through the vapor compression cycle. The refrigeration system also includes an absorption refrigeration cycle (30) having an absorber (32) and a desorbed (34) arranged in a generally closed loop configuration. An absorption solution is configured to circulate through the absorption refrigeration cycle. The vapor compression cycle and the absorption refrigeration cycle are substantially integrated. The absorber is fluidly coupled to the compressor and is configured to generate a mixture of refrigerant and absorption solution. The desorber is fluidly coupled to the condenser and is configured to separate the refrigerant from the mixture and increase a pressure of the refrigerant vapor.